Process of producing borneol esters.



. duction of Borneo] UNITED STATES PATENT OFFICE.

ENGELBERT BERGS, OF LUDWIGSHAFEN -ON-TH.E-RHINE, GERMANY, ASSI GNOR TO BADISCH'E ANILIN dz SODA FABRIK, OF LUDWIGSHAFEN-ON-THE-RHINE, GERMANY, A CORPORA- .TION.

PROCESS OF PRODUCING BOBNEOL ESTERS.

:To all whom it may concern:

l Be it known that I, ENGELBERT BERGS, doctor of philosophy and chemist, subject of the King of Prussia, residing at Ludwigshafen-on-the-Rhine, Germany, have inventednew and useful Im' rovements in the Prosters, of which the following is a specification.

My invention relates to the production from inene hydrochlorid of borneol esters mclu ing under this name both the borneol I esters proper and the isomeric bodies termed contains small isoborneo esters.

It 1s stated in the Annalen 239, page 6, and m the Bem'chte 82, 2308, that by treating pinen'e hydrochlori with sodium acetate,

or potassium acetate, at a high temperature,

'forin'stance at from 180 to 200 centigrade,

c'amphene can be obtained mixed with small luantities of bornyl acetate, or isobornyl acetate. It is further stated in the Ber'ichte 32, p. 2309, that by allowing silver acetate to act on pinene hydrochlorid for several weeks at a low temperature, a mixture is obtained which consists chiefly of camphene, but also u'antities of isobornyl acetate. It is furt er stated in the specification of the French patent No. 349,896 that by actin on pinene hydrochlorid with lead.

acetate or from twenty, to thirty, hours, either, at the temperature of boiling glacial acetic acid, or in an autoclave at a temperature of from 130 to 135 centigrade, camphene is obtained, whereas, when these two other in the presence of glacial acetic acid in compounds are allowed to act upon one anan autoclave at a temperature of 180 centigrade, bornyl acetate and isobornylacetate are thech'ief products obtained. This last method of obtaining the esters is not, however, suitable for being carried out on a com- -'mercial scale because of the 'diiliculty of working in anautoclave with glacial acetic 'acid/ at such a high temperature.

1 have now discovered that by actin on pinenmhydrochlorid with a zinc salt 0 an organic acid, such as zinc acetate, the reaction proceeds differently, ,in that by boiling these two compounds together in a reflux apparatus in the presence of a medium such as gilaciel acetic acid, after a short time a pro not is 'obtained wh1ch is free from Specification of Letters Patent.

Application filed October 23, 1906.

Patented Nov. 3, 1908.

Serial No. 340,206.

(Specimens) zinc acetate has been used, can be distilled, some of the product being bornyl acetate and some isobornyl acetate. Instead of zinc acetate, the zinc salts of other organic acids, for instance, zinc formats and zinc benzoate can be employed, and other media can be employed in place of 'lacial acetic acid, for instance formic aci or diluted acetic acid (containing for example eighty per cent. of acetic acid). When diluted acid is employed, the time required to complete the reaction is longer than when pure acid is used. The reaction which takes place can be represented by the'equation ZQ H I-ICl+Zn(OCOCH,),

ZnOl, ec,,,n,,ococn,.

Both the isomeric esters ossess the formula O,,,H,,OCOCH and the difference of constitution between them is not known. The ro ortion of isomeric esters to one another 1n t 0 product a pears to vary according to the method in w iich the reaction is carried out, but it is a matter of indifference in what proportions they occur, for in both forms the orneol ester is equally useful for practical purposes, namely, for the manufacture of cam hor.

T e following example will serve to illustrate further the nature of my invention and a way in which it can be carried into practical cifect, but my invention is not confined to this example. The parts are by weight. Boil together, for about fortyfivc (45) minutes, in arefiux apparatus, one hundred (100) parts of solid pinene hydrochlorid, fifty-four (-54) warts of Zinc acetate and one hundred andfii to stand for some time, then distil oil the acetic acid in vacuo and wash the residue with water, and then distil. The mixture of the esters distils over at a pressure of about twelve (12) millimeters of mercurv, at a temperature of from one hundred and two (102), to one hundred and five (105), degrees centigrade, and the said esters. can easily be saponified and the corresponding alcohols be produced.

Now what I claim is:

1. The production of borneol esters by ty (150) parts of lacial acetic acid. Allow the mixture tocoo slowly and chlorin and from which borneol acetate, if

heeting [)jL'LGIlB hydrochlorid Withazinc salt of my hand in the presence of two subscribing an organic acid 1n the presence of an organic witnesses.

acid substantially as hereinbefore described. v

2. The production of borneol esters by ENGE'LBERT BERGS' 5 heating inene hydrochlcrid with zinc ace- Witnesses:

tate in t e presence of acetic acid. ERNEST F. EHRHARDT,

In testimonv whereof I have hereunto set H. W. HARRIS. 

